Re: [Rats] TPM background for RIV

[Ira McDonald <[e-mail]>]

Hi Michael,

Sorry for the confusion.

No, the MCP doesn't forbid PCR8-PCR15, but it doesn't prescribe
their usage either.  No impact on RIV for network equipment.  I was
merely noting that TPM 2.0 Library is largely silent on specifics of
PCR usage.  And there is presently no TPM 2.0 profile for network
equipment.

Cheers,
- Ira



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On Tue, Aug 25, 2020 at 6:29 PM Michael Richardson <[e-mail]> wrote:

> Ira McDonald <[e-mail]> wrote:
>     > Small note:  Although you say each TPM has at least 16 PCRs, in fact
> the
>     > TPM 2.0 Mobile Common Profile
>     > (2015) only requires the implementation of one SHA-256 bank of 8
> PCRs (a
>     > SHA-1 bank is prohibited here).
>     > That design choice was made to avoid the squabbles over the
> inconsistent
>     > usage of PCR8 through PCR15
>     > across various TPM 2.0 profiles.
>
> I just want to understand.
> TPM 2 mobile, only requires PCR0-7.  It doesn't forbid PCR8->15 though?
> Do devices tend to implement them all?  Or?
>
> So what do the profiles do now?
>
> What is the impact on RIV?
>
> --
> ]               Never tell me the odds!                 | ipv6 mesh
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